3½ Inch Tie-in to 4 Inch Main Wye

New! EXTRA Heavy-Duty 4" Wye with 3½" Tie-In. Built for durability and reliability, this fitting is the French Drain Man Team’s preferred way to bring a 3½" lateral into a 4" main line—without choking flow.

The 4" Wye body maintains smooth, efficient water movement in the main line, while the included 3½" female coupler provides a secure, leak-resistant connection for your 3½" branch. The result: clean transitions, minimal turbulence, and a pro-grade tie-in that stands up to real-world loads.

Trust the choice of professionals—choose our EXTRA Heavy-Duty 3½" Tie-in to 4" Main Wye for your next drainage project.

Why Pros Choose It

• Purpose-built tie-in: Integrates a 3½" lateral line to a 4" main without bottlenecks.
• High-flow geometry: Wye design preserves main-line velocity and reduces turbulence.
• Secure 3½" connection: Includes a 3½" female coupler for a snug, dependable fit.
• EXTRA heavy-duty construction: Engineered for buried installations and tough job-site conditions.
• Time & labour saver: Faster, cleaner tie-ins mean less trench time and fewer callbacks.

What’s Included

• (1) EXTRA Heavy-Duty 4" Wye
• (1) 3½" Female Coupler (for the lateral tie-in)

Compatibility

• Main line: 4" (compatible with FDM 4" systems and most 4" drainage lines)
• Lateral tie-in: 3½" (compatible with FDM 3½" lines)

Typical Uses

• Tying 3½" downspout runs into a 4" yard drain
• Adding new branches to existing 4" mains
• Optimising system flow where T-fittings would create turbulence